*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}
html {
    font-size: 100%;
}
body {
    font-family: system-ui, sans-serif;
    line-height: 1.5;
    color: #333;
    background: #f9f9f9;
    padding: 1rem;
}
header {
    text-align: center;
    margin-bottom: 2rem;
}
header .tagline {
    font-size: 1.2rem;
    color: #555;
}
section {
    margin-bottom: 2rem;
}
h2 {
    font-size: 1.5rem;
    margin-bottom: .5rem;
}
.img-grid {
    display: grid;
    gap: .5rem;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
}
.img-grid img {
    width: 100%;
    height: auto;
    object-fit: cover;
    border-radius: .4rem;
    opacity: 0;
    animation: fadeIn 1s forwards;
    animation-delay: calc(var(--i) * .2s);
}.rsvp-btn {
    display: inline-block;
    padding: .75rem 1.5rem;
    font-size: 1rem;
    color: #fff;
    background: #0066cc;
    border: none;
    border-radius: .4rem;
    cursor: pointer;
    transition: background .3s ease, transform .3s ease;
}
.rsvp-btn:hover,
.rsvp-btn:focus {
    background: #004999;
    transform: scale(1.05);
}
#cta {
    text-align: center;
}
#cta h2 {
    animation: pulse 2s infinite;
}

@keyframes fadeIn {
    to { opacity: 1; }
}
@keyframes pulse {
    0%, 100% { transform: scale(1); }
    50%      { transform: scale(1.08); }
}
@media (min-width: 600px) {
    body { padding: 2rem; }
}